unix: Add if_indextoname and IF_NAMESIZE
unix: Add if_indextoname and IF_NAMESIZE

superriva/libc,philippkeller/libc,philippkeller/libc,cybergeek94/libc,zethra/libc,rust-lang/libc,anatol/libc,superriva/libc,cactorium/libc,superriva/libc,anatol/libc,cactorium/libc,cactorium/libc,rust-lang-nursery/libc,rust-lang/libc,mneumann/libc,zethra/libc,mneumann/libc,mneumann/libc,cybergeek94/libc,philippkeller/libc,rust-lang-nursery/libc,rust-lang/libc,rust-lang-nursery/libc,zethra/libc,cybergeek94/libc,anatol/libc